Profound osteopenia is a frequent and often irreversible complication of anorexia nervosa (AN). Adolescents with AN often have a reduced peak bone mass and are at increased risk for early osteoporosis and fractures. These young women have subnormal serum levels of gonadal steroids and the adrenal androgen dehydroepiandrosterone (DHEA) that may be associated with their low bone mineral density (BMD). Low DHEA levels are accompanied by decreased levels of insulin-like growth factor I (IGF-I), estrogen, and testosterone. Previous data from our group indicate that oral DHEA therapy in young women with AN: increases lean body mass, serum levels of bone formation markers and insulin-like growth factor I (IGF-I), and decreases urinary markers of bone resorption. We also found that standard hormonal replacement therapy (HRT) significantly decreased bone resorption markers. Information on the effects of these therapies on bone strength and ultimate fracture risk is lacking.